This Part Fits the following kits / parts:

#87032 - REVERSE MODULE (SAVAGE)

Savage/Need 3ch (Switching type) radio system (Includes 3servos.)

Get out of tight jams with the Reverse Module for the Savage
Monster Truck! Uses any servo (or #80559 SF-1 Servo) to activate reverse gear.

Easy to operate with any 3-channel radio such as the standard TF-4
radio included with the Savage RTR trucks! For the Savage X or any
Savage with 2-channel radio installed, the #307 Reverse Mixer Pro
is required. All necessary linkage and full instructions are
included in the box for quick installation.